Agent Skills: Actor Isolation Fixer

Actor Isolation Fixer

Instructions

Fix actor isolation errors systematically:

1. Error: "main actor-isolated property X cannot be accessed from nonisolated"

   • In deinit: Mark property as nonisolated(unsafe) private var
   • In closure: Add @MainActor to Task or use await MainActor.run { }
   • In method: Mark method @MainActor or nonisolated

2. Common Leavn patterns:

   // Timer in @MainActor class deinit
   nonisolated(unsafe) private var timer: Timer?
   
   deinit {
       timer?.invalidate() // Safe - Timer.invalidate() is thread-safe
   }
   
   // Task property in @MainActor class
   nonisolated(unsafe) private var task: Task<Void, Never>?
   
   deinit {
       task?.cancel() // Safe - Task.cancel() is thread-safe
   }
   

3. Don't use nonisolated(unsafe) for:

   • UI properties (views, layers)
   • Mutable state accessed across threads
   • Non-thread-safe types

4. Safe to use nonisolated(unsafe) for:

   • Timers (invalidate is thread-safe)
   • Tasks (cancel is thread-safe)
   • Notification observers (removeObserver is thread-safe)

Use this skill when: Actor isolation errors, deinit cannot access properties, concurrent access violations